Now that more and more survey research is being conducted, its important we don't use an expensive and possibly incorrect data collection method. There are two main types of research, qualitative and quantitative, and the two are very different in both purpose and execution.
Qualitative research is by definition an exploratory form of data collection, and it should be used when you don’t know what to expect from a population. It is also typically used to define your problem when you are unsure of what your problem is, or to perhaps develop an approach to your problem. It’s also used to go deeper into issues of interest and explore issues related to the problem at hand. Common data collection methods used in qualitative research are focus groups, dyads or triads, in-depth cognitive interviews, uninterrupted observation, bulletin boards and participation/observation.
Qualitative research methods will be most useful to you when you need to develop an initial understanding of an issue or problem and the scope of that problem, you'd like to look for a range of ideas and feelings about a topic, understand the different aspects or opinions amongst different groups of people, uncover underlying motivations and factors that influence decision making, provide info needed to design a quantitative study, or to explain findings from a quantitative study to your clients.
Make sure you select the approach (quantitative or qualitative data collection) that best fits your research objectives. We should never assume that building an extra-long quantitative survey will give you all the in-depth information you can get though conducting a focus group, despite the increased cost.